Global site-specific N-glycosylation analysis of HIV envelope glycoprotein
Ontology highlight
ABSTRACT:
INSTRUMENT(S): Orbitrap Fusion
ORGANISM(S): Homo Sapiens (ncbitaxon:9606)
SUBMITTER: 
James C. Paulson
PROVIDER: MSV000080530 | MassIVE | Mon Feb 06 16:16:00 GMT 2017
REPOSITORIES: MassIVE
Similar Datasets
Project description:HIV-1 envelope glycoprotein (Env) is the sole target for broadly neutralizing antibodies (bnAbs) and the focus for design of an antibody-based HIV vaccine. The Env trimer is covered by ∼90N-linked glycans, which shield the underlying protein from immune surveillance. bNAbs to HIV develop during infection, with many showing dependence on glycans for binding to Env. The ability to routinely assess the glycan type at each glycosylation site may facilitate design of improved vaccine candidates. Here we present a general mass spectrometry-based proteomics strategy that uses specific endoglycosidases to introduce mass signatures that distinguish peptide glycosites that are unoccupied or occupied by high-mannose/hybrid or complex-type glycans. The method yields >95% sequence coverage for Env, provides semi-quantitative analysis of the glycosylation status at each glycosite. We find that most glycosites in recombinant Env trimers are fully occupied by glycans, varying in the proportion of high-mannose/hybrid and complex-type glycans.
| S-EPMC5379070 | biostudies-literature
Project description:Impact of Common Modifications on the Antigenic Profile and Glycosylation of Membrane-Expressed HIV-1 Envelope Glycoprotein
Recent HIV-1 vaccine development has centered on near native soluble envelope glycoprotein (Env) trimers. These trimers are artificially stabilized laterally (between protomers) and apically (between gp120 and gp41). These same stabilizing mutations have been leveraged for use in membrane-expressed Env mRNA vaccines, although their precise effects in this context are unclear. To address this question, we investigated the effects of Env mutations expressed on virus-like particle (VLP) in 293T cells. Uncleaved (UNC) trimers were laterally unstable upon gentle lysis from membranes. However, gp120/gp41 processing improved lateral stability. Due to inefficient gp120/gp41 processing, UNC is incorporated into VLPs. A linker between gp120 and gp41 (NFL) neither improved trimer stability nor its antigenic profile. An artificially introduced enterokinase cleavage site allowed processing post-expression, resulting in increased trimer stability. Gp41 N-helix mutations I559P and NT1-5 both imparted lateral trimer stability, but concomitantly reduced gp120/gp41 processing and/or impacted V2 apex and interface NAb binding. I559P consistently reduced recognition by HIV+ donor plasmas, further supporting antigenic differences. Mutations in the gp120 bridging sheet failed to stabilize membrane trimers in a pre-fusion conformation, reduced gp120/gp41 processing and exposed non-neutralizing epitopes. Reduced glycan maturation and increased sequon skipping were common effect of mutations. In some cases, this may be due to increased rigidity which limits access to glycan processing enzymes. In contrast, viral gp120 did not show glycan skipping. We observed a minor species of high mannose glycan only gp160 in particle preparations. This was unaffected by any mutations and instead bypasses normal folding and glycan maturation processes. Including the full gp41 cytoplasmic tail led to markedly reduced gp120/gp41 processing and increased the proportion of high mannose gp160. Remarkably, NAbs were unable to bind to full-length Env trimers. Overall, our findings suggest caution in leveraging mutations to ensure they impart valuable membrane trimer phenotypes for vaccine use.
The files enclosed are labelled according to the enzyme used in the digest. T = Trypsin, C = Chymotrypsin, A = Alpha-lytic protease
2023-07-12 | MSV000092416 | MassIVE
Project description:Comparison of cells expressing or not expressing the HCV envelope glycoprotein, E1E2, reveals upregulation of host endoplasmic reticulum stress pathways, including genes such as HSPA5 and ATF3
2022-03-07 | GSE163239 | GEO
Project description:The envelope glycoprotein GP of the ebolaviruses is essential for host cell attachment and entry. It is also the primary target of the protective and neutralizing antibody response in both natural infection and vaccination. GP is heavily glycosylated with up to 17 predicted N-linked sites, numerous O-linked glycans in its disordered mucin-like domain (MLD), and three predicted C-linked mannosylation sites. Glycosylation of GP is important for host cell attachment to cell-surface lectins, as well as GP stability and fusion activity. Moreover, it has been shown to shield GP from neutralizing activity of serum antibodies. Here, we use mass spectrometry-based glycoproteomics to profile the site-specific glycosylation patterns of ebolavirus GP, including N-, O-, and C-linked glycans.
2022-08-02 | PXD031459 | Pride
Project description:The envelope (Env) glycoprotein on the surface of human immunodeficiency virus type 1 (HIV-1) which decorated with a dense array of glycans is a determinant for viral invasion and host immune response of HIV-1 and a major target for a preventive HIV-1 vaccine. Improved vaccine design requires an understanding of the detailed information about the glycan type on each glycosite. Here, we used our well-established sequential glycoproteomic workflow to characterize the N/O-glycosylation of HIV-1 gp120 at the level of native intact glycopeptides based on a stepped collision energy/higher-energy collisional dissociation (sceHCD) mass spectrometry (sceHCD-MS/MS), and a combined electron transfer/higher-energy collisional dissociation (EThcD) and sceHCD mass spectrometry (EThcD-sceHCD-MS/MS).
2021-11-03 | PXD025078 | Pride
Project description:The mature HIV-1 envelope (Env) glycoprotein is composed of gp120, the exterior subunit, and gp41, the transmembrane subunit assembled as trimer by noncovalent interaction. There is a great body of literature to prove that gp120 binds to CD4 first, then to the co-receptor. We have recently demonstrated that gp120 cannot bind to the co-receptor without first interacting with CD4. Previous studies provided different glycomic maps for the HIV-1 gp120. Here, we build on previous work to report that the use of LC-MS/MS, in conjunction with hydrophilic interaction liquid chromatography (HILIC) enrichment to glycosylation sites, is associated with the assorted neutralizing or binding events of glycosylation targeted antibodies from different clades or strains. In this study, the microheterogeneity of the glycosylation from 4 different clades of gp120s is deeply investigated. Aberrant glycosylation patterns were detected on gp120 originated from different clades, viral sequences and host cells. The results of this study may help provide better understanding of the mechanism of how the glycans participate in antibody neutralizing process that target glycosylation sites.
2021-11-01 | PXD027353 | Pride
Project description:Zika virus (ZIKV) is a mosquito-transmitted positive-sense RNA virus in the family Flaviviridae. Live attenuated vaccines have been successfully used to combat infection by flaviviruses, such as yellow fever and Japanese encephalitis viruses. A Zika virus harboring combined mutations in the envelope protein glycosylation site and in the nonstructural 4B protein amino acid 36 (ZE4B-36) was generated and assessed for stability, attenuation, and protection against infection. To determine the genetic stability of its RNA genome, ZE4B-36 was serially passaged in vitro in Vero cells. Virus harvested from passages (P)1 to P6 was subjected to next generation sequencing and downstream analysis to determine its nucleotide sequence variability. Specifically, single nucleotide variant analysis showed that the ZE4B-36 genome decreased its genetic diversity and resulted in a more stable nucleotide sequence. Thus, in addition to showing attenuation and protection, ZE4B-36 is a stable live attenuated virus that possesses characteristics important for a vaccine to combat Zika disease.
2021-12-31 | E-MTAB-9496 | biostudies-arrayexpress
Project description:The chemokine receptor CCR5 is a major co-receptor for human immunodeficiency virus 1 (HIV-1) mediating infection of target cells1,2. Beyond its function as co-receptor, CCR5 also influences the course of HIV disease and progression to AIDS3. However, it is unclear how CCR5 affects HIV-associated damage to the central nervous system (CNS) and development of HIV-associated neurocognitive disorders (HAND) independently of its co-receptor function. Here we show in a transgenic model of brain damage induced by HIV envelope protein gp1204 that genetic ablation of CCR5 prevents neuronal injury and loss and limits microglial activation, but fails to abrogate astrocytosis. CCR5 deficiency also protected gp120-transgenic mice against impairment of spatial learning and memory. Thus, CCR5-deficiency revealed that astrocytosis, a prominent pathological feature of AIDS brains5, can occur independently from neuronal demise and behavioral impairment. Since the viral envelope protein expressed in the transgenic mouse model originated from HIV-1 LAV4, a CXCR4-preferring virus that can infect macrophages6, CCR5 appeared to exert its control of neuronal injury predominantly in an indirect fashion and independently from its function as a co-receptor. Using analysis of genome-wide CNS gene expression we identified a subset of 734 genes that were differentially regulated in association with neuronal injury in the presence of CCR5. This subset of genes indicated that neuronal injury was associated with activation of macrophages and microglia. A set of 1305 genes was only differentially regulated in association with gp120 in the absence of CCR5 and indicated changes to leukocyte function and the anti-viral immune response besides a down-regulation of components in the GABAergic neurotransmission system. Interestingly, the most significantly differentially expressed genes were observed in a separate subset of 461 genes that was regulated in association with gp120 but independently of the CCR5 genotype. The finding that differential regulation of the 461 and 1305 gene sets was not necessarily linked to neuronal damage and loss suggested that altered expression of at least some of these factors may represent a protective adaptive response of the brain to the presence of viral gp120. Additional experiments using quantitative RT-PCR, protein assays and flow cytometry further supported the notion that CCR5 deficiency blunted microglial activation, a hallmark of HIV-associated brain injury7-9 without significantly affecting the expression of viral gp120. These results provide in vivo evidence for a significant role of CCR5 in HIV-associated CNS injury and behavioral impairment that is independent of the molecules’ function as HIV co-receptor. To characterize the neuroprotective effect of CCR5 ablation in the presence of HIV gp120, we next performed a genome-wide gene expression analysis using whole brain RNA preparations of mice from lines 1 and 2. We decided to collect samples from two time points before and after the ages of when we analyzed histopathology (6 months) and behavior (8 to 9 months) in order to identify genes for which differential regulation may be affected by an interaction of HIVgp120 expression and age. Accordingly, we collected brain tissue of gp120tg, CCR5KO x gp120tg, WT and CCR5KO mice at five different ages: 1.5, 3, 6, 12, and 20 (line 1) or 16 (line 2) months.
2014-09-09 | E-GEOD-47029 | biostudies-arrayexpress
Project description:The extensive glycosylation of HIV-1 envelope proteins (Envs), gp120/gp41, is known to play an important role in evasion of host immune response by masking key neutralization epitopes and presenting the Env glycosylation as "self" to the host immune system. The Env glycosylation is mostly conserved but continues to evolve to modulate viral infectivity. Thus, profiling Env glycosylation and distinguishing interclade and intraclade glycosylation variations are necessary components in unraveling the effects of glycosylation on Env's immunogenicity. Here, we describe a mass spectrometry-based approach to characterize the glycosylation profiles of two rVV-expressed clade C Envs by identifying the glycan motifs on each glycosylation site and determining the degree of glycosylation site occupancy. One Env is a wild-type Env, while the other is a synthetic "consensus" Env (C.CON). The observed differences in the glycosylation profiles between the two clade C Envs show that C.CON has more unutilized sites and high levels of high mannose glycans; these features mimic the glycosylation profile of a Group M consensus immunogen, CON-S. Our results also reveal a clade-specific glycosylation pattern. Discerning interclade and intraclade glycosylation variations could provide valuable information in understanding the molecular differences among the different HIV-1 clades and in designing new Env-based immunogens.
| S-EPMC2756219 | biostudies-literature
Project description:Buffering of deleterious mutations by molecular chaperones and degradation of aberrant proteins by quality control systems are both major factors that can impact the mutational landscape available to a client protein. The impacts of the proteostasis network on protein evolution are not limited to just endogenous clients, but can also shape the mutational landscapes accessible to rapidly evolving viral proteins. Here, we test the hypothesis that the composition of the host cell’s endoplasmic reticulum (ER) proteostasis network shapes the evolution of RNA viruses by focusing on human immunodeficiency virus-1 envelope (Env), a membrane glycoprotein that folds and matures in the host cell’s secretory pathway. We apply chemical genetic methods to activate the IRE1-XBP1s and/or the ATF6 transcriptional arms of the unfolded protein response in a stress-independent manner. We then quantitatively assess the impact of the resulting altered host cell ER proteostasis environments on the relative enrichment of all Env single amino acid substitutions using deep mutational scanning. We find that upregulation of host ER proteostasis factors globally reduces the mutational tolerance of HIV-1 Env, particularly upon induction of the IRE1-XBP1s transcriptional arm of the UPR. The effects of ATF6 activation are less global, but still significant at particular Env sites. The impact of the XBP1s-induced ER proteostasis environment is disparate for diverse structural elements of Env. Conserved, functionally important regions generally exhibit the largest decreases in mutational tolerance upon XBP1s activation. In contrast, specific regions of Env, including regions targeted by broadly neutralizing antibodies, display greatly enhanced mutational tolerance when XBP1s is activated. Altogether, these data reveal a new set of host factors that specifically shape the mutational space accessible to HIV Env and, more generally, provide compelling evidence that UPR-regulated proteostasis mechanisms play critical roles in membrane protein evolution.
2022-01-30 | GSE171356 | GEO